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United States Patent |
5,003,347
|
Kameda
|
March 26, 1991
|
Opening-closing mechanism for automatic document feeder
Abstract
A mechanism for opening and closing an automatic document feeder comprising
a body-side support portion having a post removably insertable into a
mount cavity in the body of an apparatus, a feeder-side support portion
biased upward by a coiled spring, a pivot pivotally movably supporting the
feeder-side support portion on the body-side support portion, positioning
means for determining the distance between the pivot and the body, and
adjusting means for varying the distance determined by the positioning
means.
Inventors:
|
Kameda; Kiyoshige (Higashiosaka, JP)
|
Assignee:
|
Mita Industrial Co., Ltd. (Osaka, JP)
|
Appl. No.:
|
438294 |
Filed:
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November 16, 1989 |
Foreign Application Priority Data
| Nov 26, 1988[JP] | 63-298496 |
Current U.S. Class: |
355/75; 355/25; 355/72 |
Intern'l Class: |
G03B 027/62 |
Field of Search: |
355/75,25,47,72
352/72
|
References Cited
U.S. Patent Documents
T920009 | Mar., 1974 | Kosarko | 352/72.
|
1962031 | Jun., 1934 | Porter | 352/72.
|
2339202 | Jan., 1944 | Stechbart | 352/72.
|
3601335 | Aug., 1971 | Dopkins et al. | 352/72.
|
4853750 | Aug., 1989 | Murata et al. | 355/75.
|
Primary Examiner: Hayes; Monroe H.
Attorney, Agent or Firm: Jordan and Hamburg
Claims
What is claimed is:
1. A mechanism for opening and closing an automatic document feeder
comprising: support means including:
a body-side support portion having a post removably insertable into a mount
cavity in the body of an apparatus,
a feeder-side support portion for holding the automatic document feeder;
a pivot member provided on the body-side support portion for pivotally
movably supporting the feeder-side support portion; and
a spring member provided between the body-side support portion and the
feeder-side support portion for biasing the feeder-side support portion
upward;
regulation means for regulating the distance between the pivot member of
the body-side portion and the body of the apparatus, the regulation means
including:
a movable support member movably provided between the body-side support
portion and the body of the apparatus for supporting the support means,
and
an adjusting member for adjusting the position of the movable support
member; whereby the distance between the pivot member of the body-side
supporting portion and the body of the apparatus is regulated by adjusting
the portion of the movable support member by the adjusting member.
2. The mechanism of claim 1 further comprising an elastic member interposed
between the post and the wall of the body defining the mount cavity for
pressing the post into contact with the cavity-defining wall.
3. The mechanism of claim 1 wherein the movable support member is pivotably
attached to the body-side support portion.
4. The mechanism of claim 3 wherein the movable support member has an
opening, and the adjusting member includes a stopper member formed with a
flange portion having a width greater than the width of the opening, and a
stem portion having a width smaller than the width of the opening, the
stem portion extending through the opening and rotatably attached to the
body-side support portion, whereby the stopper member is rotated so as to
stop the movable support member at a desired position with the flange
portion.
5. The mechanism of claim 2, wherein the elastic member is a plate spring,
and the post has a U-shaped cross section, a part of the plate spring is
placed in the post.
Description
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to an opening-closing mechanism for use with
image forming apparatus such as copying machines and facsimile systems.
Image forming apparatus such as copying machines and facsimile systems are
known which are equipped with an openable automatic document feeder
(hereinafter referred to as "ADF"). Opening-closing mechanisms for ADFs
include those which are easily attachable to and removable from the body
of the image forming apparatus.
Such an opening-closing mechanism for ADFs will be described with reference
to FIGS. 4 and 5 which are side elevations in section. The opening-closing
mechanism 1 comprises a body-side support assembly 2', an ADF-side support
portion 3 and a spring member 4.
The body-side support assembly 2' has a frame 20, side walls 22 formed by
upwardly bending opposite side portions of the frame 20, a post 23, a
pivot 24 and a positioning member 29. The post 23 is provided on the
bottom of the frame 20. The ADF 7 is mounted on the body 6 of an image
forming apparatus by inserting the post 23 into a mount cavity 61 in the
body 6. The pivot 24 is provided on the rear portion of the frame 20 for
movably supporting the ADF-side support portion 3. The positioning member
29 is fixed to the frame 20 as projected downward from the front end of
the frame by a predetermined length so that when the ADF 7 is closed, the
document conveyor belt 72 of the ADF 7 is positioned approximately
parallel to the body 6.
The ADF-side support portion 3 is secured to an ADF cover 71 inside thereof
and supported by the pivot 24 on the frame 20 to render the ADF 7 openable
about the pivot 24. The support portion 3 is biased upward, i.e., in the
direction to open the ADF 7, by the spring member 4 which has one end held
in a cutout 31 and the other end held to the body-side support assembly
2'. The ADF 7 can be opened by lifting a knob 73 at the front end of the
cover 71 with a force F of about 1.5 kg W which is small relative to the
weight of the ADF 7.
The spring member 4 comprises a coiled spring 41 and holders 42, 43. The
holder 43 on the cover side holds one end of the coiled spring 41 and has
a lateral projecting pin 44, by which the holder 43 is retained in the
cutout 31. The holder 42 holds the other end of the coiled spring 41 and
has a lateral projecting pin 45, by which the holder 42 is held to the
support assembly 2'. The coiled spring 41 is held in place as compressed
by the holders 42, 43 to bias the ADF-side support portion 3 obliquely
upward with the spring force. The force of the spring 41 is so determined
that when the ADF 7 is opened, for example, through an angle of 60 to 70
degrees, the force of the spring 41 is in balance with the weight of the
ADF 7 to hold the ADF 7 at the opened position with this angle.
With the ADF opening-closing mechanism described above, the coiled spring
41 is given a great force for biasing the ADF 7 obliquely upward so as to
minimize the force F required to open the ADF 7 and to diminish the impact
to be produced when the ADF 7 is closed under gravity. Accordingly, when
the ADF 7 is in its closed state in which the force of the spring 41 is
greatest, the cover 71 of the ADF 7 warps as shown in FIG. 6.
Consequently, one side of the ADF 7 where the opening-closing mechanism 1
is provided will be raised off the glass platen 62, failing to position
the document conveyor belt 72 in parallel to the apparatus body 6. It is
then likely that the document will not be transported onto the glass
platen 62 properly.
This drawback may be overcome by using an iron plate, aluminum plate or
like rigid body for the cover 71, whereas the use of iron plate or the
like results in an increased weight, which entails the necessity of giving
a greater force to the spring 41 and enhanced rigidity to the entire
opening-closing mechanism 1 and the problem of an increased cost.
Further when the ADF 7 is in its closed state, the coiled spring 41 biases
the holder 42 obliquely downward, subjecting the post 23 to a
counterclockwise moment about the pivot 24. The post 23 is inclined
forward with its lower end portion pressed against the rear lower portion
of the wall defining the mount cavity 61 and with its upper end portion
pressed against the front upper portion of the wall further because the
front-rear width of the post 23 is made slightly smaller than the inside
diameter of the cavity 61 to render the ADF mountable on the body 6 with
ease.
With the post 23 thus inclined forward relative to the ADF 7, the ADF 7 is
displaced forward from the apparatus body 6 by being pushed forward, with
the result that the document to be transported onto the glass platen 62 of
the body 6 is also displaced forward.
This objection may be obviated by fastening the rear side of the post 23 to
the rear portion of the cavity-defining wall as with screws, but this
requires a cumbersome time-consuming procedure, makes the ADF 7 difficult
to mount and remove, and necessitates an increased number of parts
including the screws and an increased cost.
SUMMARY OF THE INVENTION
The main object of the present invention is to overcome the foregoing
problems and to provide at a relatively low cost an ADF opening-closing
mechanism which permits proper transport of documents onto the glass
platen.
The present invention provides a mechanism for opening and closing an
automatic document feeder, the mechanism being characterized in that it
comprises a body-side support portion having a post removably insertable
into a mount cavity in the body of an apparatus, a feeder-side support
portion biased upward by a coiled spring, a pivot pivotally movably
supporting the feeder-side support portion on the body-side support
portion, positioning means for determining the distance between the pivot
and the body, and adjusting means for varying the distance determined by
the positioning means.
With the ADF opening-closing mechanism of the above construction, the
distance between the pivot and the body as determined by the positioning
means is variable by the adjusting means to thereby lower one side of the
ADF where the mechanism is provided. This obviates the warp of the ADF
that would result when the coiled spring is given an increased force,
permitting the document conveyor belt of the ADF to be positioned in
parallel to the body for the belt to transport documents onto the glass
platen properly
The invention further provides a mechanism for opening and closing an
automatic document feeder mountable on the body of an apparatus by
inserting a post into a mount cavity in the body and biased upward by a
coiled spring, the mechanism being characterized in that an elastic member
is interposed between the post and the wall of the body defining the mount
cavity for pressing the post into contact with the cavity-defining wall.
With the ADF opening-closing mechanism stated above, the post is pressed
against the cavity-defining wall when the post is inserted into the mount
cavity of the body. Consequently, the ADF is prevented from backlashing
although it is easy to removably mount on the body by inserting the post
into the cavity. This ensures accurate transport of documents onto the
glass platen.
The above and other objects, features and advantages of the present
invention will become apparent from the following description with
reference to the drawings concerned.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of an ADF opening-closing mechanism
embodying the invention;
FIGS. 2 and 3 are views for illustrating the operation of the
opening-closing mechanism of FIG. 1;
FIGS. 4 and 5 are views showing the construction of a conventional ADF
opening-closing mechanism; and
FIG. 6 is a view for illustrating the problem encountered with the
conventional ADF opening-closing mechanism.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is an exploded perspective view of an ADF opening-closing mechanism
embodying the invention. Throughout the drawings, like parts are
designated by like reference numerals.
The opening-closing mechanism 1 comprises a body-side support assembly 2,
ADF-side support portion 3, spring member 4 and adjusting member 5. The
support assembly 2 comprises a frame 20, side walls 21, 22 formed by
bending opposite side portions of the frame 20 upward, a post 23 and a
pivot 24. The frame 20 is formed at a suitable position with a screw hole
25 which is internally threaded for an adjusting bolt 56 to be screwed in.
The side wall 21 has at a suitable position a screw hole 26 with a diameter
larger than the outside diameter of a pivot member 54. The pivot member 54
is loosely passed through the hole 26 and then driven into the screw hole
57 to be described below. The side wall 22 is formed at a suitable
position with a screw hole 27 which is internally threaded for a pivot
member 55 to be tightly screwed in.
The post 23 is U-shaped in cross section and has its opening directed
forward. An ADF 7 is mounted on the body 6 of an apparatus by inserting
the post 23 into a mount cavity 61 in the body 6. A plate spring (elastic
member) 28 is, for example, U-shaped in section and is secured at its one
end to the post 23 inside thereof, with the bulging portion directed
downward When the post 23 is inserted into the mount cavity 61, the other
end of the plate spring 28 is brought into pressing contact with the front
side of the inner wall of the body defining the cavity 61, whereby the ADF
7 is prevented from backlashing.
The adjusting member 5 comprises a base 50, a positioning portion 51 formed
by bending the front end portion of the base 50 downward and having a
predetermined length, side walls 52, 53 formed by bending opposite side
portions of the base 50 upward, the above-mentioned pivot members 54, 55
each in the form of a screw or the like, and the adjusting bolt 56 for
connecting the adjusting member 5 to the body-side support assembly 2.
The positioning portion 51 is so formed that the lower end 511 thereof
bears on the top surface 63 of the body 6 when the opening-closing
mechanism 1 is mounted on the body 6. The spring member 4 comprises a pair
of coiled springs 40, 41. The force of these springs biases the support
assembly 2 obliquely downward through a holder 42, whereby the assembly 2
is subjected to a clockwise moment about the lower end 511.
The side wall 52 is formed at a suitable position with a screw hole 57
(mentioned above) which is internally threaded. When the pivot member 54
is tightly screwed into the hole 57 through the screw hole 26, the
adjusting member 5 is fixed to the support assembly 2.
In corresponding relation to the screw hole 57 in the side wall 52, the
side wall 53 has a screw hole 58 with a diameter larger than the outside
diameter of the pivot member 55. The pivot member 55 fixed to the screw
hole 27 loosely extends through the hole 58.
When the pivot member 54 through the screw hole 26 is loosely screwed into
the screw hole 57, with the pivot member 55 through the screw hole 27
loosely inserted through the screw hole 58, the adjusting member 5 is
connected to the body-side support assembly 2 by the pivot members 54, 55
movably about these members. The base 50 has at a suitable portion a slot
59 elongated lengthwise of the base 50. The adjusting bolt 56 is loosely
inserted through the slot 59 with a spring washer or the like provided on
the bolt. When the ADF 7 is lowered as supported by the lower end 511 of
the positioning portion 51, with the adjusting bolt 56 loosened as will be
described later, the adjusting member 5 is tiltable as supported by the
pivot members 54, 55 so that the base 50 is always in contact with the
head of the adjusting bolt 56.
The pivot member 54, when tightly screwed into the hole 57, fastens the
adjusting member 5 to the body-side support assembly 2.
The adjusting member 5 may be made pivotally movable relative to the
support assembly 2 at all times by using rivets or the like as the pivot
members 54, 55 and loosely inserting the pivot member 54 through the screw
holes 26, 57 and the pivot member 55 through the screw holes 27, 58.
The clearance between the body 6 and the ADF 7 is adjustable by screwing
the adjusting bolt 56 into the screw hole 25 in the support assembly 2 by
a specified amount. The slot 59 guides the adjusting bolt 56 so that the
bolt 56 will not be bent when loosened to tilt the adjusting member 5.
For example when the ADF 7 is mounted on the body 6 with the adjusting bolt
56 tightened up as seen in FIG. 2, the force of the coiled springs 40, 41
biases the ADF 7 upward to warp the cover 71, whereby one side of the
conveyor belt 72 toward the mechanism 1 is raised off the glass platen 62.
When the adjusting bolt 56 is loosened from above with the mechanism 1
opened in this state, the post 23 lowers along the mount cavity 61 owing
to a clockwise moment about the lower end 511 of the positioning portion
51. The pivot 24 supporting on the support assembly 2 the ADF-side support
portion 3 attached to the cover 71 therefore lowers, with the result that
the cover 71 lowers at its one side where the mechanism 1 is provided.
The adjusting bolt 56 is so adjusted that the document conveyor belt 72
will be positioned in parallel to the glass platen 62 when the ADF 7 is
closed as seen in FIG. 3.
Since the adjusting bolt 56 can be thus loosened from above for adjustment
after opening the mechanism 1 with the ADF 7 mounted on the body 6, the
conveyor belt 72 can be positioned in parallel to the body 6 by a simple
procedure. Furthermore, the opening-closing mechanism 1 can be produced at
a low cost because the adjusting member 5 has a relatively simple
construction.
Although the present invention has been fully described by way of example
with reference to the accompanying drawings, it is to be understood that
various changed and modifications will be apparent to those skilled in the
art. Therefore, unless otherwise such changes and modifications depart
from the scope of the invention, they should be construed as being
included therein.
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